The following description relates to a medical monitoring system having multiple communications channels, e.g., for providing alternative information pathways between a medical monitoring unit and a central monitoring station.
Advances in sensor technology, electronics, and communications have made it possible for physiological characteristics of patients to be monitored even when the patients are ambulatory and not in continuous, direct contact with a hospital monitoring system. For example, U.S. Pat. No. 5,959,529 describes a monitoring system in which the patient carries a remote monitoring unit with associated physiological sensors. The remote monitoring unit conducts a continuous monitoring of one or more physiological characteristics of the patient, such as the patient's heartbeat and its waveform, according to a medical condition of the patient.
An objective of such portable monitoring systems is to establish contact with a central; monitoring station (a.k.a., a central unit), which is in turn may contact with medical personnel and/or access the patient's medical records. The ability to establish contact allows the central unit to determine the existence of a medical emergency with the patient, and to render medical assistance to the patient during such an emergency. The ability to establish contact is also important psychologically to the patient, so that the patient knows that (s)he is not alone or out of touch. The portable monitoring systems may establish one or more communication links to the central unit through telephone land-lines, when the patient is in a location where land-line telephone access is readily available or through the cellular telephone system when land-line access is not available or an emergency suddenly occurs.